1. Field of the Invention
The present invention relates to a program control apparatus, method and program for restricting activation of an expansion program, which operates under a basic program, based upon the combination of the basic program and expansion program.
2. Description of the Related Art
A large number of applications have been filed on license management methods as methods of controlling program activation. For example, software to undergo license management is encrypted and, based upon information such as a license number that has been input by a user, a license issuance server issues a key for decrypting the software. A license management service receives the key and decrypts the software that is the object of license management. At this time, by using information specific to a machine on which the license management service runs, execution of the software by another machine is inhibited (e.g., see the specification of Japanese Patent Application Laid-Open No. 2005-78167).
Further, a DVD player is an example of an apparatus in which a regional limitation is implemented. Playback of DVD video is inhibited in a DVD player if a region code of the DVD player and a region code of DVD video do not match.
However, the prior art described above cannot deal with a situation in which the license scheme of expansion software differs for every destination. For example, there are cases where an expansion program distributed free of charge in a specific region is sold under license in another region. In such cases, activation of an expansion program distributed freely in another region cannot be suppressed in a region in which the program is sold under license. As a consequence, a program that rightfully should be available for pay can be utilized free of charge.
DVD players implement a regional playback restriction. However, only one region code can be recorded on one medium. Consequently, it is difficult to apply this technique to a package that provides an expansion program intended for a plurality of destinations by a single medium, by way of example. Further, although a DVD has its content subjected to copy control, a region code is not subjected to encryption or signature. This means that in a case where a medium not subjected to copy control is used as a medium for supplying software, inappropriate lifting of the regional restriction becomes possible as by forging a region code.